Tag: glass

Sea Glass – Is It Trash or What?

By Anupum Pant

In the Glass Beach, a beach in MacKerricher State Park near Fort Bragg, California, like the name tells you, you’d normally find too many glass pieces on the beach. These glass pieces that people often find in beaches like these, aren’t exactly those sharp shards of glass that are sharp enough to harm you. Rather they are physically and chemically weathered pieces of glass –  round and small.

sea glass 4

This type of glass is called sea glass and has been a fancy of those hobbyists who like collecting these pieces to make beautiful adornments.

This kind of glass, often found on some beaches usually starts as shards of broken glass from dump or other such sources. In about a span of 1-2 years, the tumbling and weathering makes these pieces smooth and rounded. And then they are collectively known as “genuine sea glass”

At this particular beach in California, the beach glass that has formed over the years, first started coming in when residents who lived close to the beach started dumping garbage into the beach. Local clean up services tried to clean up the mess, but most of it had already gone in for natural weathering by that time.

Soon after the clean-up services came around, the beach became a great place for hobbyists to collect these naturally weathered beautiful glass pieces. All the trash that was first thought to be a mess, now became a tourist attraction – Naturally weathered genuine sea glass was a thing of natural beauty now. And then this smuggling of sea glass by tourists had to stop. First the mess had to stop, now the mess being taken away by tourists had to stop.

And once the glass has started to go away, now there is a move to replace all the glass – that was once considered garbage!

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Is Glass Liquid Or Solid

By Anupum Pant

Glass stories have tormented me for years. A few well informed gentlemen, over the years, have communicated to me anecdotes that have contradicted and shown glass as liquid or solid, without solid proofs that could have helped me believe just one of them. A few days back, like I cleared my doubts about the gas station and cellphone story, I decided to find this out too. So, what is it really? Is glass liquid or solid?

Glass is a liquid?

1. Antique glass panes: A couple of years back I was told (I don’t remember where it came from) that glass windows of very old buildings have glass panes that have been found to be thicker at the bottom. That, according to them, absolutely proves that glass is a liquid that flows very slowly. And apparently explains, how the lower parts of these old panes get thicker – the glass from the upper part of the pane flows down as time passes. I thought it would be something like the world’s slowest experiment; so it could be true.

Till today, I had believed the same. It turns out, I was wrong all along.

Explanation: Firstly, there is no statistical study ever conducted that proves, all antique window panes are thicker at the bottom. Secondly, even if all of them are really thicker at the bottom, the difference in thickness has nothing to do with whether glass is a solid or a liquid. The cause of thicker bottoms is due to the fact that glass manufacturing process that was employed at the time wasn’t able to create perfect glass panes (with uniform thickness). The process made it almost impossible to produce glass panes of constant thickness.

Or, you could simply wait for a few years to see if perfect glass panes stuck on skyscrapers today mysteriously turn thicker in the bottom.

If you think you can NOT take my word for it, I have a quote for you from a distinguished science textbook – Glass Science – below:

Glass is an amorphous solid. A material is amorphous when it has no long-range order, that is, when there is no regularity in the arrangement of its molecular constituents on a scale larger than a few times the size of these groups. A solid is a rigid material; it does not flow when it is subjected to moderate forces. – Doremus, R. H. (1994)

2. Glass is a Super-cooled liquid? : This misunderstood phrase from Gustav Tammann’s book is probably the origin of the myth that glass is a liquid. The quote “glass is a frozen supercooled liquid” has been misquoted hundreds of times with the word “frozen”, forgotten. Today, this misquotation has grown to such great levels that it is actually difficult to go down and extricate the original quote that contained the word “frozen” in it. One word can indeed make a huge difference.

Finally, glasses are only amorphous solids. Where the term amorphous and solid have been separately been explained clearly in the year 1994 by Doremus R. H.
Together, these two words mean the same as definition of two separate words put together. Glass is not a liquid.

If you haven’t read about the ancient Nanotech marvel, Lycurgus cup, you are probably missing something amazing about ancient glass technology.

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Lycurgus Cup – An Ancient Nanotech Marvel

By Anupum Pant

The concepts of modern nanotechnology must have been first seeded in the year 1959 by the renowned physicist Richard Feynman, but Romans were already doing it back in 300 AD (around 290-325 AD). About 1700 years back, utilizing the principles of Nanotechnology, Roman engineers had crafted a magnificent chalice – Lycurgus Cup (picture). Like the Prince Rupert’s drop, this is another glass marvel you should know about.

Side note: You can listen to the legendary lecture by Dr. Feynman on YouTube – There’s Plenty of Room at the Bottom, where he discusses the “possibility of synthesis via direct manipulation of atoms”, or Nanotechnology.

Lycurgus cup description

The Lycurgus cup was probably the first ever optical artificial [meta]material – Ruby Glass – engineered to have properties that may not be found in nature. Its unusual optical properties are something that makes it stand out.

Normally, the cup appears green, but if it is illuminated from the inside or lit up using a light placed behind it, it glows ruby-red; hence the name, ruby glass. This kind of glass is known as a Dichroic glass. Dichroic  literally means ”two colored” and is derived from the Greek words ”di” for two, and ”chroma” for color; in this case, the colors green and red.

The technology behind this cup baffled scientists for around 40 years (from 1950s to 1990s). It was only in 1990s that they figured out how it really worked. The goblet has been preserved well, and is presently at display in the British Museum.

Dichroic glass

Dichroic glasses do not use paints, dyes, or any coloring agents for the color. They are made using fine coatings on glass. The coatings themselves do not have a color, but rather they bend light to reflect colors like a prism does, to make rainbows.

These colors are visible due to the presence of very minute amounts of finely ground gold and silver particles in it. Romans could have included these powders unknowingly as contaminants or might have added them on purpose to achieve the very effect, we’ll never know.

Inspired by an age-old technology

NASA, in the 1950s, used a similar technology to fabricate a kind of glass that could selectively reflect light wavelengths. They achieved this by depositing a thin-film of metal on the glass.

With innumerable combinations of oxides, glass colors and patterns available, the possibilities to utilize this phenomenon for various useful purposes are endless.
The unusual properties of this cup have also inspired material scientists to create concepts for an invisibility cloak using modern nanofabrication technology. [Source]

I want to study interesting materials like these

If you think the Lycurgus cup, Wolverine’s claws and Aerogels (If you haven’t heard about it, you must definitely check this out!) are awesome. You can make a career in researching materials like these by making a foray into Materials Science and Engineering. Most good universities offer a course in it. It is a budding field, growing at a rapid pace, replete with real-world challenging conundrums waiting to be resolved.

Prince Rupert’s Drop – Exploding Glass

By Anupum Pant

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What is it?

At first, a Prince Rupert’s Drop is an interesting yet harmless looking drop of glass with a long tail. It looks like a tadpole: [image]

It is no different from an annoyed person who refuses to let out his resentment – A slightest something might make him explode suddenly, but it isn’t easy to make him let it out. Confused? Read on…

Now, think of a glass drop that has immense amounts of potential energy stored inside it – It explodes (actually implodes) when the tail is disturbed, but it is impossible to hit it hard with a hammer and break it.

How?

A Prince Rupert’s Drop is formed when a drop of molten glass is suddenly dropped into a water bath. This quick cooling, solidifies the surface fast, while the inner part remains molten. Now, glass formed on the surface, being a poor conductor of heat doesn’t allow the inner part to cool quickly. When the inner part starts cooling, it tries to shrink and pulls the surface towards it. As a result, great amount of potential energy gets stored inside, in the form of stresses (stresses are seen using a polarized filter). This stored energy gets released when the tail is disturbed – It explodes into very tiny pieces of glass.

Toughened glass – a stronger variety of glass used in several places – also uses a similar technique to make strengthened glass.

On Wikipedia, a user asked about the possibility of utilizing the energy released from this explosion, being used to fire a bullet from a barrel. An interesting possibility, I must say.

The Name

Prince Rupert of Rhine did not discover the drops, but played a role in bringing them to Britain. He gave them to King Charles II, who in turn delivered them to the Royal Society for scientific study. Prince Rupert’s Drop was a widely known phenomenon among the educated during the 17th century – far more than now.

Watch it being explained better

Probably the best demonstration of this glass drop exploding is right here on the internet. Couple of months back, a YouTuber, Destin (Channel: SmarterEveryDay) posted a video demonstrating the physics behind it. He recorded  the progression of the explosive fracture using a hi-speed camera (at more than 100,000 frames per second) and calculated the speed of the fracture travelling through its tail (~ 1.5 miles per second). I’ve attached it below for you to watch.